Capsule, Device and Method for Preparing a Beverage by Extraction

ABSTRACT

The invention relates to a capsule for use in a device for preparing beverages. The invention also relates to an assembly of such a capsule and a device for preparing beverages. The invention further relates to a method for preparing beverages by making use of such an assembly.

The invention relates to a capsule for use in a device for preparing beverages. The invention also relates to an assembly of such a capsule and a device for preparing beverages. In addition, the invention relates to a perforation structure evidently intended for use in such a capsule according to the invention. The invention also relates to the use of such a capsule in a device for preparing beverages. The invention further relates to a method for preparing beverages by making use of such an assembly.

Diverse capsules for use in a device for preparing beverages are known in the prior art. A known capsule as described for instance in EP 0512468 comprises a housing provided with a perforable supply side for injecting a liquid into the housing and with a discharge side located at a distance from the supply side and provided with an opening for the purpose of discharging liquid injected into the housing, a quantity of substance for extraction received in the housing, such as ground coffee beans, and a pierceable foil connected to the housing and sealing the opening located on the discharge side. This known capsule can be placed in a device for preparing a beverage. The capsule is placed for this purpose in a receiving space of a capsule holder of the device. The capsule is clampingly supported here in the receiving space by a support and a clamp. The supply side of a housing of the capsule is perforated by subsequently moving a liquid injector through the housing of the capsule, and a relatively hot liquid, in particular water, can be introduced into the housing under a relatively high pressure, generally of between 15 and 20 bar. The foil is perforated by moving a perforation plate forming part of the capsule holder and the capsule toward each other and the extracted liquid flows via the perforation plate into a beverage container. A drawback of using this known capsule and device for preparing a beverage while making use of such a capsule is that the device requires relatively high maintenance. There is therefore a need for a device requiring less maintenance.

An object of the invention is to provide for the above stated need.

The invention provides for this purpose a capsule of the type stated in the preamble, comprising: a housing at least partially filled with a substance to be extracted and/or dissolved, such as ground coffee, wherein the housing is provided with a supply side for pressing a liquid such as water into the capsule, and with a discharge side located a distance from the supply side for discharging liquid provided with extract and/or dissolved substance and guided through the capsule, wherein at least a part of the discharge side of the housing is initially sealed by a perforable foil; a laterally protruding engaging edge connected to the housing to enable clamping of the capsule in a device for preparing beverages; and a perforation structure coupled substantially rigidly to the engaging edge and/or the housing and provided with at least one perforation element facing toward the foil for perforating the foil, which perforation structure is positioned substantially on a side of the foil remote from the housing, wherein perforation of the foil is caused by deformation of the foil during pressing of the liquid through the capsule. By providing the capsule with its own perforation structure for perforating the foil a conventional perforation plate forming part of the device is no longer required. The advantage hereof is that the prepared beverage need no longer be pressed through the conventional perforation plate of the device, but can optionally be delivered directly from the capsule to a drinking cup. This can drastically reduce the beverage residue left behind in the device, this being advantageous from a hygiene viewpoint and reducing the required maintenance on the device. It is moreover possible in this way to prevent, or at least counter, beverage pressed out of the capsule mixing with beverage residues coming from one or more already used capsules and already present in the device, whereby the taste of the beverage to be prepared can be guaranteed as fully as possible. The perforation structure will be connected substantially rigidly (non-displaceably) to the housing, whereby the external dimensioning of the capsule must generally be smaller than or the same as a volume enclosed by the capsule holder. The perforation structure will generally be provided with one or more throughflow channels or throughfeed openings extending between a side of the perforation structure facing toward the foil and a side of the perforation structure remote from the foil. The particular advantage here is that the number of throughflow channels to be applied and the dimensioning of these throughflow channels can be wholly adapted to the nature of the beverage to be prepared, wherein the intensity of the aeration, the extent of the pressure buildup and the swirling of the beverage pressed out of the capsule can be regulated, which can considerably enhance the taste sensation during consumption of the beverage. Because the foil will be perforated by the generally pointed perforation elements and will be pressed during use against the perforation structure, a filtering action will be realized, whereby solid constituents such as coffee dregs can be kept in the housing. The supply side will otherwise generally take a closed form initially, wherein the supply side will be perforated in the device during use. It is also possible to envisage the supply side already being pre-perforated during the production process, whereby further perforation in the device can be dispensed with. The drawback hereof is however that the capsule generally has to be packaged in order to enable a sufficiently long shelf-life of the substance, and therefore of the capsule. Initial, substantially hermetic sealing of the capsule is generally recommended, wherein the capsule can optionally be filled with an inert gas, such as nitrogen or carbon dioxide, in order to further increase the shelf-life of the substance. The result hereof is that a slight overpressure of several hundred millibar will generally be present in the capsule. This overpressure can possibly increase to some extent if coffee powder, which naturally generates a limited amount of gas, is received in the capsule.

The housing can be manufactured from diverse materials, including an aluminum and/or plastic, in particular polypropylene (PP). When a plastic housing is applied, the housing will generally be manufactured from a laminate of a plurality of plastic layers, such as PP and ethylene vinyl alcohol (EVOH). When an aluminum housing is applied, it is generally also usual to laminate the aluminum with one or more additional layers, including a protective lacquer coating in order to avoid direct contact of aluminum with the beverage to be prepared, and including for instance a PP layer to enable realization of an (ultrasonic) welded connection to the foil. The foil generally also comprises aluminum which is optionally provided on one or two sides with a PP layer in order to facilitate one or two-sided adhesion of the foil. It is also possible to envisage the foil comprising aluminum oxide (ALOX), optionally laminated with plastic such as polyethylene terephthalate (PET), whereby an exceptionally thin foil can be obtained with a thickness in the order of magnitude of several microns. The foil is generally connected by means of welding and/or adhesion to the engaging edge, in particular to a flange forming part of the housing.

The perforation structure usually takes a plate-like form in order to limit the volume taken up by the capsule. The perforation structure is preferably positioned at least partially in a volume enclosed by the housing. The advantage hereof is that the dimensioning of the housing need not be adapted to the standard dimensioning of a capsule and capsule holder, this being advantageous from an economic point of view. It is advantageous here for the perforation structure to connect substantially seamlessly to the engaging edge, wherein the perforation structure can even form an integral part of or be integrally connected to at least a part of the engaging edge. It is a further advantage that a side of the perforation structure remote from the foil and a side of the engaging edge are located in the same plane, so that a completely flat underside of the capsule can in fact be realized. The housing and the perforation structure are generally positioned initially on either side of a plane defined by (a central part of) the foil. A suitable material for a perforation structure is plastic, such as for instance PP or polyethylene (PE).

The engaging edge generally comprises at least one flange connected integrally to the housing. It is also possible to envisage the flange being chemically and/or mechanically connected to an inner side and/or outer side of the housing. The engaging edge will usually be constructed in laminated manner from at least one flange connected to the housing and a support structure coupled to the flange, the support structure being optionally integrally connected to the perforation structure. An edge periphery of the perforation structure is optionally connected via at least one connecting element to the engaging edge. The support structure will generally take a substantially annular form here, because the flange will usually have the same shape. It is possible here to envisage the support structure at least partially enclosing, and even being able to clamp, the flange. It is also possible to envisage welding and/or adhering the support structure to the flange, usually with interposing of the foil. The support structure can be constructed from a plurality of parts which are mutually connected during the production process, for instance by means of welding or adhesion.

The perforation structure and the support structure are preferably manufactured at least partially from the same material, such as polypropylene, in order to enable realization of a reliable mutual connection. As already stated, it is also possible to envisage the perforation structure and the support structure being integrally connected to each other and being manufactured in the same production step, for instance by means of injection moulding. The support structure can here in fact be deemed as an (integral) extension of the perforation structure. The support structure is preferably constructed here from a lower part initially connected directly to the perforation plate and an upper part connected to the lower part, wherein the lower part and the upper part are at least positioned at least partially on either side of the flange connected to the housing or forming part of the housing, whereby the flange is at least partially covered on an underside and an upper side by the support structure. The upper part of the support structure can be connected integrally to the lower part of the support structure, wherein the support structure is even manufactured from one material, in particular plastic, preferably polypropylene. The lower part of the support structure will however generally be adapted to initially hold (support) the perforation structure and the upper part of the support structure will generally be adapted as sealing element. It is therefore generally advantageous to select the material properties of the upper part of the support structure such that a reliable sealing of the capsule in the capsule holder can be realized. These selected material properties are preferably also such that a reliable connection can be realized between the lower part of the support structure and the upper part of the support structure. The upper part of the support structure is preferably manufactured for this purpose from a composition comprising polypropylene and an elastomeric copolymer of units of ethylene and units of an ∀-olefin, such as ethylene, propylene or 1-butene. The upper part of the support structure is preferably manufactured at least partially from a composition comprising 20-50% by weight crystalline polypropylene and 50-80% by weight elastomeric ethylene copolymer. Further details of the thermoplastic polypropylene-based elastomer are described in EP 0770106 and EP 0472946. Such thermoplastic polyolefins are commercially available under the brand names Hifax®, in particular Hifax® 7334 XEP, Adflex®, in particular Adflex® X500F, and Softell®. It is otherwise also possible to envisage providing an outer surface of the capsule with at least one other type of sealing element for sealing the capsule in the device.

In an advantageous embodiment the perforation structure is provided with a plurality of throughflow channels for discharge of liquid, the throughflow channels extending from a side of the perforation structure facing toward the foil to a side of the perforation structure remote from the foil. The perforation structure is generally also provided with a plurality of perforation elements. It is possible here to envisage at least a number of throughflow channels being located at a distance from the perforation elements. It is however also possible to envisage, and even advantageous, for at least one perforation element to be provided with one or more throughflow channels. It is found particularly advantageous in practice to apply a conical perforation element through which extend three throughflow channels which debouch in the cone wall, whereby blocking of the throughflow channels by perforated foil parts can be prevented.

For the purpose of being able to prevent blocking of an outer end of a throughflow channel by the device it is advantageous for a side of the perforation structure remote from the foil to be provided with at least one surface groove, the surface groove connecting to at least one outer end of at least one throughflow channel. It is further possible to envisage a side of the perforation structure remote from the foil being provided with a plurality of surface grooves, the surface grooves connecting the outer ends of the throughflow channels to each other. The surface grooves can connect to each other and intersect each other and in this way form a network.

The perforation elements must be sufficiently sharp to be able to perforate the foil. It is therefore advantageous that at least a number of perforation elements take a pointed, in particular pyramid-shaped and/or cone-shaped form. A cone-shaped (conical) shape is generally recommended above a pyramid-shaped embodiment, since the conical embodiment has a periphery varying less pronouncedly as seen in the height of the perforation elements, whereby the foil will tear and/or deform more gradually and therefore more easily.

An edge part of the perforation structure facing toward the foil is generally provided with one or more perforation elements for realizing an edge perforation in the foil. The perforation element can here form a cutting edge which can extend over the whole or partial edge part of the perforation structure. In addition, it is possible to envisage application of more centrally positioned perforation elements. In order to be able to guarantee a reliable perforation, it is generally advantageous that the foil initially engages under bias on at least one perforation element. This is because sufficient pressure buildup in the housing of the capsule will, as a result of the bias, result relatively quickly in perforation of the foil.

In an advantageous embodiment of the capsule a side of the perforation structure remote from the foil is provided with an upright sealing edge which protrudes in a direction away from the foil. This upright sealing edge provides on the one hand for an improved connection of the capsule to the device, and thereby for an improved sealing. The application of the upright sealing edge moreover makes the perforation structure stackable (nestable) with another perforation structure, this being particularly advantageous during the production process.

The invention also relates to an assembly of a capsule according to the invention and a device for preparing beverages, which device comprises a capsule holder for receiving the capsule. The capsule holder here preferably comprises a plurality of holder parts which are mutually displaceable between an opened state, in which the capsule can be placed in the capsule holder, and a closed state in which the engaging edge of the capsule is clamped substantially liquid-tightly by the holder parts.

The invention further relates to the use of a capsule according to the invention in a device for preparing beverages.

In addition, the invention relates to a perforation structure evidently intended for use in a capsule according to the invention. The perforation structure will generally be optionally integrally connected here to a support structure.

The invention moreover relates to a method for preparing a beverage by making use of an assembly according to the invention, comprising of: A) placing a capsule in at least a part of an opened capsule holder, B) closing the capsule holder with substantially liquid-tight clamping of the engaging edge of the capsule, C) pressing liquid, in particular water, into the capsule via the supply side of the capsule, whereby the foil will be pressed against the perforation structure and will be perforated by the at least one perforation element, and D) discharging via the perforated foil liquid guided through the capsule. During step B the supply side is generally also perforated by perforation means forming part of the capsule holder.

The invention will be elucidated on the basis of non-limitative exemplary embodiments shown in the following figures. Herein:

FIGS. 1-6 show different views of a first embodiment of a capsule, or part thereof, according to the invention;

FIGS. 7-9 show cross-sections of a capsule according to FIGS. 1-6 in a capsule holder of a device for preparing beverages;

FIG. 10 is a perspective view of a second embodiment of a capsule according to the invention;

FIG. 11 shows a cross-section of the capsule according to FIG. 10 along the line C-C;

FIG. 12 is a perspective view of the perforation structure of the capsule according to FIG. 10; and

FIG. 13 shows a cross-section of the piercing element according to FIG. 12 along the line D-D.

FIG. 1 shows a perspective view and FIG. 2 shows a cross-section of a first embodiment of a capsule 1 according to the invention. Capsule 1 comprises for this purpose a substantially frustoconical (truncated conical) housing 2 at least partially filled with a substance to be extracted and/or dissolved, such as ground coffee, tea, cocoa, milk powder and so on. Housing 2 comprises a perforable upper wall 3 which forms a supply side of capsule 1. The upper wall will be perforated in a capsule holder of a device for preparing beverages, after which water, in practice generally a mixture of water and air, is pressed into capsule 1 at a pressure of between 1 and 20 bar. Housing 2 also comprises a peripheral wall 4 which is integrally connected to upper wall 3 and which tapers to some extent in the direction of upper wall 3, wherein in the shown situation peripheral wall 4 encloses an angle with the vertical lying between 5° and 7°, this angle of inclination corresponding to the complementary angle of inclination of a number of capsule holders available on the market, whereby the volume of housing 2 can be maximized. Peripheral wall 4 is provided with a ridge 5 to enable better fitting of capsule 1 on many of the known capsule holders. Housing 2 further comprises a plurality of strengthening elements 6 arranged recessed into upper wall 3 and/or peripheral wall 4. Strengthening elements 6 resist deformation of housing 2 as much as possible during use. In addition, housing 2 comprises a flange 7 which is integrally connected to the peripheral wall (see FIG. 2) and which as such forms part of an engaging edge 14 of capsule 1, this engaging edge 14 being adapted to allow clamping of capsule 1 by the capsule holder. An inner edge of flange 7 does in fact define (a part of) the discharge side of capsule 1, this discharge side being initially sealed substantially medium-tightly by a foil 8 connected to flange 7. The connection between flange 7 and foil 8 is preferably realized by means of (ultrasonic) heat welding, whereby a relatively reliable connection can be realized between flange 7 and foil 8. It is advantageous here for the contact surfaces for fusing together to be manufactured from the same material, such as PP. Flange 7 is clamped by and/or enclosed by and/or connected to a support structure 9 for a plate-like perforation structure 10. In this exemplary embodiment support structure 9 is connected integrally to perforation structure 10. Support structure 9 has a modular construction of an upper part 9 a and a lower part 9 b connected, preferably welded, to upper part 9 a. Upper part 9 a of support structure 9 is in principle adapted to seal capsule 1 in the capsule holder, while lower part 9 b of support structure 9 is in principle adapted to initially hold perforation structure 10. Upper part 9 a and lower part 9 b can optionally be connected as separate elements to flange 7. As shown in FIG. 2, perforation structure 10 is substantially wholly enclosed by a volume enclosed by housing 2, wherein housing 2 and perforation structure 10 are separated by foil 8. In this exemplary embodiment perforation structure 10 comprises a plurality of perforation elements 12. All perforation elements 12 are embodied pyramid-shaped and have a pointed outer end directed toward foil 8 and are adapted to perforate foil 8. Between perforation elements 12 are throughflow channels 13 extending from an upper side of perforation structure 10 to an underside of perforation structure 10 in order to enable discharge of water enriched with the substance, i.e. the prepared beverage, in capsule 1. As shown in FIG. 2, the diameter of throughflow channels 13 increases to some extent in the direction of an underside of perforation structure 10, this enhancing discharge of prepared average from capsule 1 as well as aeration of the beverage. Also shown is that an underside of perforation structure 10 takes a substantially flat form and also defines an underside of capsule 1. The underside of perforation structure 10 and an underside of engaging edge 11 moreover lie in the same plane, this enhancing handling (storage, transport and use) of capsule 1. In the shown initial situation foil 8 engages on substantially all perforation elements 12, such however that foil 8 remains intact (closed). FIG. 2 further shows that perforation structure 10 comprises an upright peripheral edge 14 which is located in housing 2 which protrudes just as far as perforation elements 12 and which can be used to attach foil 8 thereto, whereby foil 8 no longer need be connected to flange 7, which can be advantageous from a structural viewpoint.

During clamping of the capsule in a capsule holder upper wall 3 of capsule 1 will generally be perforated by one or more cutting elements forming part of the capsule holder, after which, during the preparation process, water—and generally air—will be pressed into the capsule at a pressure of between 1 and 20 bar, whereby foil 8 is pressed against perforation elements 12, whereby foil 8 will be perforated. The assembly of perforated foil 8 and perforation structure 10 will act here as filter, wherein beverage will be allowed through and solid parts, in particular residue, will be held back.

During the clamping particularly engaging edge 11 of capsule 1 is clamped in order to realize a seal between capsule 1 and the capsule holder. It is advantageous here for upper part 9 a of support structure 9 to be manufactured from a resilient material such as a TPO. A reliable seal of the capsule in the capsule holder is realized by the thermoplastic character of the material of upper part 9 a of support structure 9. Other than conventional thermosetting elastomers (rubber elastomers), thermoplastic polymers are manufactured using equipment suitable for processing resins. Thermoplastic polymers are quicker and easier to manufacture than thermosetting elastomers, which are manufactured in three lengthy steps (mixing, injection moulding and cross-linking). Other than thermosetting polymers, thermoplastic polymers can moreover be fully or partially recycled. Since lower part 9 b of support structure 9 is generally manufactured at least partially from PP and ultrasonic welding is recommended to mutually connect lower part 9 b and upper part 9 a, it is advantageous for a thermoplastic polypropylene-based elastomer to be applied, such as Adflex®, in particular Adflex® X500F.

FIG. 3 is a perspective view and FIG. 4 is a top view of the assembly of support structure 9 and the perforation structure 10 connected (integrally) to support structure 9. FIG. 3 shows that perforation elements 12 take a pyramid-shaped form. Cone-shaped (conical) perforation elements can optionally be used instead, which can also be advantageous. Throughflow channels 13 are positioned between perforation elements 12. Perforation elements 12 can optionally be provided with throughflow channels. FIG. 4 shows the regular arrangement of perforation elements 12 and the throughflow channels 13 located therebetween. The size and positioning of throughflow channels 13 and the number of throughflow channels 13 can be adapted to the nature of the beverage to be prepared. The pressure buildup in the capsule can for instance be increased by making throughflow channels 13 smaller, whereby more substance will generally be carried by the water, this resulting in a stronger beverage. Engaging edge 14 of perforation structure 10 can be adapted to engage with clamping fit or under bias on an inner side of housing 2, whereby an improved edge seal can be obtained between housing 2 and perforation structure 10, whereby water is forced to leave capsule 1 via throughflow channels 13. Instead of using the above stated edge seal, it is also possible to envisage connecting the perforation structure 10 and/or the support structure 9 connected (integrally) thereto to housing 2, in particular to the flange 7 forming part of housing 2, for instance by means of welding and/or adhesion.

FIG. 5 is a bottom view of capsule 1, which shows that the diameter of throughflow channels 13 increases in the direction of the underside of perforation structure 10. The underside of perforation structure 10 can optionally be provided with a network of surface grooves mutually connecting the lower outer ends of throughflow channels 13, whereby possible sealing of throughflow channels 13 by the capsule holder, and thereby blockage of capsule 1, can be prevented. FIG. 6 is a side view of the assembly according to FIGS. 3-5, showing particularly that perforation elements 12 protrude no further than engaging edge 14 of perforation structure 10.

In the shown first embodiment of capsule 1 according to the invention the following product specifications can be applied. In the case a plastic housing 2 is applied, the wall thickness thereof can vary and be adapted to the functionality of the relevant part of housing 2. The thickness of flange 7 can for instance amount to between 0.30 and 0.65 mm, while the thickness of the upper wall amounts to 0.15 mm. A slight overpressure of 200 to 300 mbar is present in capsule 1 so that deformation of capsule 1 can be resisted prior to use, foil 8 can be pressed against perforation structure 10 and as much oxygen as possible driven out of capsule 1 during the production process. A typical height of the central perforation elements 12 amounts to between 1 and 2 mm, wherein the length of throughflow channels 13 preferably lies between 0.3 and 0.45 mm. The (narrowest) diameter of throughflow channels 13 amounts to between 0.7 and 0.9 mm. The width of connecting elements 11 amounts in this example to between 1 and 2 mm. The overall thickness of engaging edge 14 amounts to about 1.0 mm, wherein the thickness of flange 7 preferably lies between 0.3 and 0.4 mm, the thickness of foil 8 amounts to about 0.02 mm, the thickness of upper part 9 a of support structure 9 amounts to about 0.3 mm and the thickness of lower part 9 b of support structure 9 also amounts to about 0.3 mm. Applying the above stated dimensioning results in a capsule with a relatively large internal volume of about 14 cm³.

FIGS. 7 and 9 show different cross-sections of a capsule 1 as according to FIGS. 1-6 in a capsule holder 15 of a device for preparing beverages such as a coffee machine, in an opened situation prior to use of capsule 1 (FIG. 7) and in a closed situation in which the beverage can be prepared (FIG. 8), and in a closed situation in which water is pressed through capsule 1 (FIG. 9). Capsule holder 15 here comprises a first holder part 15 a and a second holder part 15 b displaceable relative to first holder part 15 a. First holder part 15 a comprises one or more cutting elements 16 for perforating upper wall 3 of capsule 1. First holder part 15 a further comprises a clamping edge 17 for pressing engaging edge 11 onto second holder part 15 b such that capsule holder 15 is sealed substantially completely liquid-tightly, whereby leakage of water via the formed seam can be prevented. Second holder part 15 b is provided with one or more discharge openings 18 for beverage. During closing of capsule holder 15 by displacing first holder part 15 a and second holder part 15 b toward each other the upper wall 3 of capsule 1 will be perforated, and engaging edge 11 will be clamped substantially liquid-tightly between the two holder parts 15 a, 15 b. Foil 8 will remain intact during this clamping, as also shown in FIG. 8. Water will then be pressed via the perforated upper wall 3 into capsule 1 at a pressure of between 1 and 20 bar, whereby water comes into contact with a substance received in the housing, such as coffee powder or instant coffee, whereby the water is transformed into coffee. This injection of water into capsule 1 results in a pressure buildup in capsule 1 which is so great that foil 8 will deform in the direction of perforation structure 10 and will be perforated by perforation elements 12, after which the water can be removed from capsule 2 via throughflow channels 13 (see FIG. 9).

Referring to FIG. 10, a capsule designated in its entirety with 21 is shown. Capsule 21 comprises a housing 22 manufactured from a plastic. The housing comprises a pierceable supply side for water 22 a and a discharge side 22 b which is located at a distance from the supply side for water 22 a and provided with an opening for discharge of water injected into the housing. The opening on discharge side 22 b is sealed by a pierceable, flexible foil 25. On the discharge side housing 22 comprises a support edge 22 c, whereby capsule 21 can be placed unambiguously in a device for preparing beverages and does not displace, or hardly so, during use. Capsule 21 will moreover be clamped by the device via support edge 22 c. Foil 25 is connected here to housing 22 by means of an adhesive connection or welded connection to support edge 22 c and a part of the inner side of housing 22 close to support edge 22 c (see also FIG. 11). The strength of foil 25 and the adhesive connection between foil 25 and housing 22 is sufficiently strong to withstand the force obtained during guiding of water under a pre-known pressure into capsule 21. Housing 22 is connected to a plate-like perforation structure 26. Perforation structure 26 is situated on the side of foil 25 facing toward the outer side of the housing. Perforation structure 26 is provided with a plurality of continuous openings 27 which are distributed over perforation structure 26 and which form an outer end of throughflow channels 28 arranged in perforation structure 26 for discharge of water guided through capsule 21. On the side of perforation structure 26 facing toward the inner side, i.e. the side of perforation structure 26 facing toward the foil, the perforation structure 26 comprises a plurality of protrusions placed distributed over the surface of perforation structure 26 and formed as pyramids 29 (see also FIG. 11). Pyramids 29 comprised tips 30 for piercing foil 25 from the outer side of capsule 21. Openings 27 are located here between pyramids 29. In the situation shown here foil 25 rests on perforation structure 26. When water is guided under pressure into capsule 21, a force F will be exerted on foil 25, wherein this force will urge foil 25 in the direction of the perforation structure 26 provided with pyramids 29. If this force F exceeds a determined value, the tips 30 of the pyramids will perforate foil 25. Extracted liquid will hereby be guided out of capsule 21 via channels 28 and outside capsule 21. Because capsule 21 comprises its own perforation structure 26, no separate piercing element is required as is necessary with use of the known capsules. This makes the device for preparing a beverage not only simpler, since the beverage can flow directly out of capsule 21 through the openings and channels 28 into a beverage container, the risk of contamination of the device is also reduced. The device hereby requires less maintenance, thereby increasing convenience of use.

FIG. 11 shows a cross-sectional view of the capsule according to FIG. 10 along the line C-C. Although the housing of the capsule 21 shown here is formed as a truncated cone, the housing of the capsule can also be embodied as a cylinder or in other conceivable form.

FIG. 12 shows the piercing element of capsule 21 according to FIG. 10 embodied as perforation structure 26. FIG. 13 shows a section along line D-D of the piercing element according to FIG. 12 embodied as perforation structure 26. Perforation structure 26 here comprises a peripheral edge 31 for placing perforation structure 26 in housing 22. Peripheral edge 31 can also be employed for (liquid-tight) attachment of the foil. Perforation structure 26 is also provided with a flange 32 which is connected integrally to peripheral edge 31 and which can be deemed as support structure of perforation structure 26. Perforation structure 26 will be connected here via the flange 32 functioning as support structure to the flange 22 c forming an integral part of housing 22.

It will be apparent that the invention is not limited to the exemplary embodiments shown and described here, but that within the scope of the appended claims numerous variants are possible which will be self-evident to the skilled person in the field. 

1. A capsule for preparing beverages, comprising: a housing at least partially filled with a substance to be extracted and/or dissolved, such as ground coffee, wherein the housing is provided with a supply side for pressing a liquid such as water into the capsule, and with a discharge side located a distance from the supply side for discharging liquid provided with extract and/or dissolved substance and guided through the capsule, wherein at least a part of the discharge side of the housing is initially sealed by a perforable foil; a laterally protruding engaging edge connected to the housing to enable clamping of the capsule in a device for preparing beverages; and a perforation structure coupled substantially rigidly to the engaging edge and/or the housing and provided with at least one perforation element facing toward the foil for perforating the foil, which perforation structure is positioned substantially on a side of the foil remote from the housing, wherein perforation of the foil is caused by deformation of the foil during pressing of the liquid through the capsule.
 2. The capsule as claimed in claim 1, wherein the perforation structure is positioned at least partially in a volume enclosed by the housing.
 3. The capsule as claimed in claim 2, wherein the perforation structure is connected integrally to at least a part of the engaging edge.
 4. The capsule as claimed in claim 1, wherein the foil initially seals the housing substantially medium-tightly.
 5. The capsule as claimed in claim 1, wherein the perforation structure takes a substantially plate-like form.
 6. The capsule as claimed in claim 1, wherein an edge periphery of the perforation structure is connected via at least one connecting element to the engaging edge.
 7. The capsule as claimed in foregoing claims claim 1, wherein the engaging edge comprises at least one flange connected integrally to the housing.
 8. The capsule as claimed in claim 1, wherein the engaging edge has a laminated structure and comprises at least one flange connected to the housing and a support structure coupled to the flange and connected to the perforation structure.
 9. The capsule as claimed in claim 1, wherein a side of the perforation structure remote from the foil and a side of the engaging edge are located in the same plane.
 10. The capsule as claimed in claim 1, wherein at least a part of the engaging edge is manufactured from a resilient material, in particular an elastomer, more particularly a rubber elastomer.
 11. The capsule as claimed in claim 10, wherein the resilient material comprises polypropylene.
 12. The capsule as claimed in claim 10, wherein the resilient material is manufactured at least partially from a thermoplastic polyolefin (TPO).
 13. The capsule as claimed in claim 12, wherein the thermoplastic polyolefin resilient material comprises a composition of polyolefins comprising polypropylene and an elastomeric copolymer, the copolymer comprising units of ethylene and units of an ∀-olefin.
 14. The capsule as claimed in claim 13, wherein the ∀-olefin is formed by ethylene, propylene or 1-butene.
 15. The capsule as claimed in claim 1, wherein an outer surface of the capsule is provided with at least one sealing element for sealing the capsule in the device.
 16. The capsule as claimed in claim 1, wherein the perforation structure is provided with a plurality of throughflow channels for discharge of liquid, the throughflow channels extending from a side of the perforation structure facing toward the foil to a side of the perforation structure remote from the foil.
 17. The capsule as claimed in claim 1, wherein the perforation structure is provided with a plurality of perforation elements.
 18. The capsule as claimed in claim 16, wherein at least a number of throughflow channels are located at a distance from the perforation elements.
 19. The capsule as claimed in claim 16, wherein at least one perforation element is provided with at least one throughflow channel.
 20. The capsule as claimed in claim 16, wherein a side of the perforation structure remote from the foil is provided with at least one surface groove, the surface groove connecting to at least one outer end of at least one throughflow channel.
 21. The capsule as claimed in claim 20, wherein a side of the perforation structure remote from the foil is provided with a plurality of surface grooves, the surface grooves connecting the outer ends of the throughflow channels to each other.
 22. The capsule as claimed in claim 1, wherein at least a number of perforation elements take a pointed, in particular pyramid-shaped and/or cone-shaped form.
 23. The capsule as claimed in claim 1, wherein an edge part of the perforation structure facing toward the foil is provided with at least one perforation element for realizing an edge perforation in the foil.
 24. The capsule as claimed in claim 1, wherein the foil engages under bias on at least one perforation element.
 25. The capsule as claimed in claim 1, wherein a side of the perforation structure remote from the foil is provided with an upright sealing edge which protrudes in a direction away from the foil.
 26. The capsule as claimed in claim 1, wherein the capsule is assembled with a device for preparing beverages, which device comprises a capsule holder for receiving the capsule.
 27. The assembly as claimed in claim 26, wherein the capsule holder comprises a plurality of holder parts which are mutually displaceable between an opened position, in which the capsule can be placed in the capsule holder, and a closed position in which the engaging edge of the capsule is clamped substantially liquid-tightly by the holder parts. 28-29. (canceled)
 30. A method for preparing a beverage by making use of an assembly as claimed in claim 26, comprising the steps of: A) placing a capsule in at least a part of an opened capsule holder, B) closing the capsule holder with substantially liquid-tight clamping of the engaging edge of the capsule, C) pressing liquid, in particular water, into the capsule via the supply side of the capsule, whereby the foil will be pressed against the perforation structure and will be perforated by the at least one perforation element, and D) discharging via the perforated foil liquid guided through the capsule.
 31. The method as claimed in claim 30, wherein during closing of the capsule holder as according to step B) the supply side of the capsule is perforated by the capsule holder. 